Genesis 18:27 - Joseph Benson’s Commentary on the Old and New Testaments

Behold now, I have taken upon me to speak unto the Lord, who am but dust and ashes He speaks as one amazed at his own boldness, and the liberty God graciously allowed him, considering God's greatness, who is the Lord, and his own meanness, but dust and ashes. Whenever we draw near to God, it becomes us reverently to acknowledge the vast distance that there is between us and him. He is the Lord of glory, we are worms of the earth.